HIGH-STRENGTH HOT-ROLLED STEEL SHEET WITH EXCELLENT PROCESSING PERFORMANCE AND MANUFACTURING METHOD THEREOF, CAPABLE OF ENSURING EXCELLENT ELONGATION RATIO AND YIELD RATIO

摘要

PURPOSE: A high-strength hot-rolled steel sheet with excellent processing performance and manufacturing method thereof are provided to realize excellent elongation ratio and yield ratio by appropriately controlling ingredients and fine structure. ;CONSTITUTION: A high-strength hot-rolled steel sheet with excellent processing performance consists of 0.07-0.12weight% of C, 0.80-1.71weight% of Si, 1.5-2.5weight% of Mn, 0.5-1.0weight% of Cr, 0.1-0.3weight% of Al, 0.01-0.06weight% of Nb, below 0.005weight% of S, below 0.04weight% of P, Fe and other inevitable impurities. The elongation ratio of the hot-rolled steel sheet is over 12% and its yield ratio is below 0.750. The tensile strength of the hot-rolled steel sheet is over 980MPa. The fine structure of the hot-rolled steel sheet consists of ferrite, martensite and bainite.;COPYRIGHT KIPO 2011